Generally speaking, a printed circuit board is connected to a flexible circuit board through a surface mount board-to-board electrical connector. Usually, a plug welded on the flexible circuit board is engaged with a receptacle welded on the printed circuit board by up and down assembly, so that a contact terminal of the receptacle is electrically connected to a contact terminal of the plug.
Referring to China Patent No. 200620167704, a board-to-board electrical connector is disclosed, see FIG. 6 in the filed patent specification. The board-to-board electrical connector is formed by a first connector 1 (i.e., the plug) and a second connector 2 (i.e., the receptacle) connected to the first connector 1 by insertion. The first connector 1 includes a first body 10 and a plurality of first terminals 15. The second connector 2 includes a second body 20 and a plurality of second terminals 25. The first terminal 15 has a U-shaped upper contact portion 152, and an inner slot 1521 and an outer slot 1522 opposite to the inner slot 1521 are formed on the upper contact portion 152. The second terminal 25 has two lower contact portions 252, and the two lower contact portions 252 are respectively formed with bumps 2521. Therefore, when the first connector 1 is inserted into the second connector 2, the bumps 2521 may respectively urge against the inner slot 1521 and the outer slot 1522 to form electrical connection.
However, the development of the board-to-board electrical connector is in the trend of thin volume. In consideration of reducing the height of the board-to-board electrical connector, the above board-to-board electrical connector has the following defects. (1) The side surface of the first terminal 15 and the side surface of the second terminal 25 are in contact to form the electrical connection, so if the structure of the board-to-board electrical connector is made to be thinner, when the heights of the first terminal 15 and the second terminal 25 are reduced, it is difficult to maintain a sufficient contact area; (2) the bumps 2521 of the second terminal 25 are caught by the inner slot 1521 and the outer slot 1522 of the first terminal 15, so when the heights of the first terminal 15 and the second terminal 25 are reduced, the design technology of the bumps 2521, the inner slot 1521, and the outer slot 1522 needs to be precise and accurate, and this manner of catching is not reliable and may be easily disengaged.
Therefore, it is necessary to design a novel board-to-board electrical connector capable of solving the above problems.